Reference Guide
• Detects DCB mis-configuration in a peer device; that is, when DCB features are not compatibly configured on a
peer device and the local switch. Mis-configuration detection is feature-specific because some DCB features
support asymmetric configuration.
• Reconfigures a peer device with the DCB configuration from its configuration source if the peer device is willing
to accept configuration.
• Accepts the DCB configuration from a peer if a DCBx port is in “willing” mode to accept a peer’s DCB settings
and then internally propagates the received DCB configuration to its peer ports.
DCBx Port Roles
To enable the auto-configuration of DCBx-enabled ports and propagate DCB configurations learned from peer DCBx
devices internally to other switch ports, use the following DCBx port roles.
Auto-upstream The port advertises its own configuration to DCBx peers and is
willing
to receive peer
configuration. The port also propagates its configuration to other ports on the switch.
The first auto-upstream that is capable of receiving a peer configuration is elected as the
configuration source. The elected configuration source then internally propagates the
configuration to other auto-upstream and auto-downstream ports. A port that receives an
internally propagated configuration overwrites its local configuration with the new parameter
values. When an auto-upstream port (besides the configuration source) receives and
overwrites its configuration with internally propagated information, one of the following actions
is taken:
• If the peer configuration received is compatible with the internally propagated port
configuration, the link with the DCBx peer is enabled.
• If the received peer configuration is not compatible with the currently configured port
configuration, the link with the DCBx peer port is disabled and a syslog message for an
incompatible configuration is generated. The network administrator must then
reconfigure the peer device so that it advertises a compatible DCB configuration.
– The configuration received from a DCBx peer or from an internally propagated
configuration is not stored in the switch’s running configuration.
– On a DCBx port in an auto-upstream role, the PFC and application priority TLVs
are enabled. ETS recommend TLVs are disabled and ETS configuration TLVs
are enabled.
Auto-
downstream
The port advertises its own configuration to DCBx peers but is
not willing
to receive remote
peer configuration. The port always accepts internally propagated configurations from a
configuration source. An auto-downstream port that receives an internally propagated
configuration overwrites its local configuration with the new parameter values.
When an auto-downstream port receives and overwrites its configuration with internally
propagated information, one of the following actions is taken:
• If the peer configuration received is compatible with the internally propagated port
configuration, the link with the DCBx peer is enabled.
• If the received peer configuration is not compatible with the currently configured port
configuration, the link with the DCBx peer port is disabled and a syslog message for an
incompatible configuration is generated. The network administrator must then
reconfigure the peer device so that it advertises a compatible DCB configuration.
– The internally propagated configuration is not stored in the switch's running
configuration.
– On a DCBx port in an auto-downstream role, all PFC, application priority, ETS
recommend, and ETS configuration TLVs are enabled.
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